Unloading mechanism for compressors.



) H. CALLAN. I UNLOADING-IVIEC HANISM'FOR COMPRESSORS.

APPLICATION FILED IAN-4. I916.

Patented Aug. 13, 1918 2 SHEETS-SHEET I- INVENTOR WITNESSES mmgniws W'. H. CALLAN. UNLOADING MECHANlSM FOR COMPRESSORS.

APPLICATION FILED JAN-4.1915.

Patented Aug. 13, 1918.

2 SHEETS-SHEET Z.

INVENTOR WITN ESSES mrondmrs thii bill

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slotted to permit the same. to partially surround the central post 27 of the cylinder and such central post is connected with the main body of the cylinder by means of the oli'set or brace member preferably integral therewith, Fig. 3. This member 28 forms a guide for the forward portions of the piston 26 which longitudinally bisected at its forward portion, to form the flanges or blades 29, as will be best understood by rel? erence to Fig. 3. The flanges 29 of the piston abut against the valve lifter 30, which is guided on the valve stud 19 and is normally maintained in its raised position by means of a spring 31 interposed between the nut 13 and the hub of the valve lifter 30. The valve lifter has a flange extending forwardly from its hub portion and integral with a plate 32, which latter" is providedwith the forwardly projecting, portions 33, which are adapted to pass through the ports in the valve seat 10 in order to maintain the valve away from its seat. The piston 26 is provided with double cup leather washers 34:, which are secured in place by means of a washer and a fastening device 36, such as for example a rivet, The piston 26 tits the piston chamber 87 in the cylinder 21 and the upper end of such piston chamber 37 is made air tight by means of a close fitting threaded cap 38 in threaded engagement with the cylinder 21. The cap 38 has its upper face recessed at 39. thereby adapting, the same to receive the hub of a handle 40, said hub being provided with a cam face 41, as bestscen in Figt. The hub of the handle 40 'apertured to provide for rotatably mounting it on the pipe 42 which latter is in threaded engagement with the cap in order to provide for the admission of motive fluid into the piston chamber-37. The cam face 4]. on the handle 40 is adaptcd to cooperate with the upper end of a plunger 42) which extends through the cap 258 and whose lower end is adapted to contact with thte washer carricd by the piston 26. The lower cud of the plunger 43 is preferably enlarged. lhe pipe 42 is connected by means of a coupling 4st with a pipe 4-5 which communicates with a chamber 46 formcd in a valve 47,

which may be of any desired or conventional type.

The coupling scrvcs as one type of means to retain the cam face M. in its proper rela tion to the plunger or pin i l.

The valve 4'7 comprises a sectional casing 48 in which is located a valve -19 cont-rolling comn'iunication between the chamber 46 and. the chamber 50, which latter is in communication with the receiver by means of a conduit- 51. 52 designates uplungrcr which contacts with the valve and between the plun cr and a washer 53 is interposed a spring at,

the tension of which may be varied by proper actuation of an adjusting screw which is locked in position by means of a, nut 56.

In the automatic operation of my novel unloading, nufchanism. it will be seen that when the receiver pressure reaches the desired point, the unloader operates. Motive fluid is admitted tl'iroug'h a pipe to into a piston, chamber 37, to advance its piston 26 and thereby the valve lifter 30. This causes the valve 11- to be opened and held open until the receiver pressure has been rcduced to a point at which the differential unloader valve moves against its upper scat thus exhausting the fluid from pipe l5 and piston chamber 37. The spring 31 then forces the valve lifter and piston back into running position as seen at the left hand side of Fig. l.

When it is desired to start a direct motor mounted compressor against pressure, the manually actuated feature is employed which operates as followsz-The levers are manually operated to move thci'n lo the opening position, as seen at the right hand portion of Fig. 1.. During: this movcmcnt of the levers it), the cams on their hubs or body move the plunger -ll against the ends of their respective pistons 2H. These pistons cause the valve lifters to be moved inwardly to unseat the valves and hold them open so that the fluid instead of being compressed flows into and out of the piston chamber during the reciprm'ation of the piston. As soon as the compressor has reachcd its nor mul speed, the levers 40 are returned to the position seen in Fig. 2 and the compressing of the fluid is cll'ected in the usual manner.

I provide means independent of the rcceiver pressure to manually actuate the valves which control the communication between the air inlet and each end of the piston chamber so that when the valves are operated manually, they 'are moved by a direct and positive connection bet-ween the actuating levers and their respective pistons.

In accordance with my present invention, I provide a single unit of simplified and compact construction which may be opcr- .ated. either automatically or manually.

7 It will now be appnrcnt that I have dcvised a novel and, useful unloading mechanism i'or compressors, which embodies the features of advantage cnumcratcd as dosirablc in the statement of tho invention and the abo c description. and while I have, in the present instance, shown and described a preferred cmbodimcnt thereof which will give in practice satisfactory and reliable results. it is to be understood that the same is susccptiblc of modification iii various particulars without departing from the spirit of its advantages.

it it or scope of the invention or Having thus described my invention, What I claim as new and desire to secure by Letters Patent, is:-

1. Unloading mechanism for compressors, comprising the combination with the valves controlling communication between the piston chamber and air of valve lifters to actuate said valves, pistons to actuate said valve lifters, plungers contacting with said pistons, and means to actuate said plungers.

2. Unloading mechanism for compressors, comprising the combination [with the valves controlling communication between the piston chamber and air inlet of the compressor, of valve litters to actuate said valves, pistons to actuate said valve lifters, plunger-s contacting with. said pistons, controlled cams to actuate saidplungers.

8. Unloading mechanism for compressors, comprising the combination with valve mechanism controlling communication between the piston chamber and air inlet of the compressor, of a cylinder securing said valve mechanism in assembled position and provided With a piston chamber, a piston in said piston chamber and operatively connected with said valve to actuate it, and means to introduce motive fluid into said piston chamber to actuate said piston.

l. Unloading mechanism for compressors, comprising in combination with the receiver and valve mechanism contr'ollin communication betvvecn the piston-chain er and air sacrificing any inlet of the compressor,

and manually inlet of the compressor, of a cylinder for securing said valve mechanism in position, a piston in said cylinder, said cylinder and piston having means common to them to prevent rotatlon of the piston, a valve lifter actuated by said piston, means controlled by the receiver pressure to actuate said pis ton, and manually actuated means to move said piston to actuate the valve liiter.

5. Unloading mechanism for compressors, comprising in combination with valve mechanism controlling communication between the compression cliamber and air inlet of the compressor, of a cylinder having an extension contacting With said valve mechanism to fix it in position, a valve lifter to actuate the valve of the valve mechanism, a piston within said cylinder and guided by said extension, resilient mcans'to retain the valve lifter in operative engagement with said piston, and means toell'cct the movement of said piston.

6. Unloading mechanism for compressors, comprising the combination with the 1'5 ceiver and the valves controlling; communication between the piston chamber and air inlet of the compressor, of a valve lifter to open said valves, pistons to actuate said valve lifters, means to automatically actuate said pistons, plungers to contact with said pistons, and levers to actuate said plum gers.

Wl'lJlilAll l 'H. CALLA N. Witnesses C. H. Hansnnnu, MARY B. ECKnu'v till till 

